Glade3 is using own libglade (ver. 3), while rest of apps (and bindings)
is using older libglade (ver. 2).

glade3-libgladeui.i386
libglade2.i386

I do not think so. glade3-libgladeui and libglade2 are separate
packages providing separate things.
The first one provides a library (of widgets, etc.) that you can use
to embed Glade3 into your own application (eg., Anjuta's Glade3
plugin); or create your own Glade3 clone. The second package is a
library to parse the XML file representing the GUI created by Glade3
(and possible Gazpacho, etc.).
Cheers,
Debarshi